Over the years Miller’s leading man status faded, but he settled into leading and major supporting roles in serials for distribution by Pathé Exchange, Incorporated — many of them with costar Allene Ray. Miller remained busy throughout his film career, appearing in more than 250 short films, feature films and film serials.

Miller died working on a Republic Pictures set in 1940, appearing uncredited in a Gene Autry western.

Confusion between Walter Miller and W. Chrystie Miller is slightly compounded by the former being sometimes known as Walter C. Miller and the latter sometimes being known as W.C. Miller, and by both of them appearing in Biograph films for D.W. Griffith and other directors in 1912-1913. Website-IMDb and Website-Wikipedia have suspect and cross-pollinated information that adds to the confusion.